Fuel metering systems



1961 R. J. POWELL ET AL 2,995,125

FUEL METERING SYSTEMS Filed Dec. 28, 1959 FROM FUEL SUPPLY INVENTORS ROBERT J. POWELL BY JAMES E. CHAMPION km afig ATTORNEYS United States Patent 2,995,125 FUEL METERHJG SYSTEMS Robert J. Powell and James E. Champion, Muskegon, MiclL, assignors to Continental Motors Corporation, Muskegon, MiclL, a corporation of Virginia Filed Dec. 28, 1959, Ser. No. 862,328 6 Claims. (Cl. 123119) This invention relates to fuel metering systems for internal combustion engines and more particularly to fuel flow regulating means operable to variably meter fuel to the engine in response to engine speed and air intake manifold pressure variations.

An object of the present invention is to simplify fuel metering systems for small engines by providing a means of regulating fuel flow dependent on variations of air intake manifold pressure and engine speed as it is reflected by fuel pump delivery pressure.

Another object of the invention is to facilitate fuel metering control for internal combustion engines by providing a simplified pressure responsive fuel flow regulator.

A further object of the invention is to improve fuel metering characteristics for an engine in which fuel delivery pressure varies in response to engine speed changes by providing a fuel flow regulator actuated to vary fuel metering in response to variations of fuel delivery pressure and air intake manifold pressure.

For a more complete understanding of the invention, reference may be had to the accompanying drawing illustrating a preferred embodiment of the invention in which like reference characters refer to like parts throughout the several views and in which FIG. 1 is a diagrammatic perspective view of a preferred fuel metering system incorporating the present in vention, and

FIG. 2 is a cross-sectional view of a preferred fuel flow regulator embodied in the invention.

The preferred system is illustrated diagrammatically in FIG. 1 as adapted to an internal combustion engine 10 having cylinders 11, an air intake manifold 12 having a throttle valve 13, and an engine driven fuel pump 14 which delivers fuel through a conduit 15 under a pressure which is variable with respect to variations in engine speed.

The fuel injection system comprises, in addition to the fuel pump 14, a fuel flow regulator 16 to which the conduit 15 delivers fuel, a fuel manifold 17 which receives metered fuel from the regulator 16 through a conduit 18, and an individual fuel discharge nozzle 19 at each cylinder supplied with metered fuel through conduits 20 connected with the fuel manifold 17. A pressure sensing conduit 21 connects the regulator 16 with the air intake manifold 12 downstream of the throttle valve 13.

FIG. 2 illustrates a preferred construction of the regulator 16 as comprising a housing 25 having a fuel inlet port 26 connected to the conduit 15, a fuel outlet port 27 connected to the conduit 18, and a port 28 connected to the manifold sensing conduit 21. The housing 16 is provided with axially aligned chambers, namely a manifold pressure chamber 39 closed by an end cap 31, a fuel inlet chamber 32, and a fuel discharge chamber 33 closed by a second end cap 34, the chambers 30, 32 and 33- respectively being openly connected with the ports 28, 26, and 27 by means of passages 35, 36 and 37.

A preferred metering valve element 38 is disposed intermediate the fuel inlet and discharge chambers 32 and 33, and is provided with a metering orifice 39 openly connecting the chambers 32 and 33, the open cross-sectional area of the orifice 39 being variably controlled by means of an axially movable tapered pin 40 which is carried on the end of a plunger or piston 41 extending axially from the fuel inlet chamber 32 into the manifold pressure chamber 30. The chambers 30 and 32 are separated by means of an annular seal 42 disposed around the piston 41.

The manifold pressure chamber end of the piston 41 is connected to one end of a pressure sensitive bellows 45 disposed in the manifold pressure chamber 30 and mounted at its other end on an adjustable supporting element 46 carried by the cap 31. It will be apparent that the axial position of the tapered pin 40, which determines the fuel flow through the orifice 39 is variable with respect to variations of manifold pressure in the manifold pressure chamber 30 causing the bellows 45 to contract and expand.

The end of the piston 41 disposed in the fuel inlet chamber 32 has a pressure sensitive area 47 which acts also to elfect axial adjustment of the piston in response to variations of fuel pressure in the fuel inlet chamber 32, so that the fuel flow through the orifice 39 as regulated by the pin 40 varies as engine speed increases and decreases.

An idle stop element 48 is preferably adjustably carried by the end cap 34 and limits the valve closing movement of the tapered pin 41. The stop element as shown is preferably manually set in the present instance, where the engine 10 is used in such aircraft as drones or the like, but it will be apparent that any means can be utilized for adjustment to act as an idle mixture control. Opening movement of the piston 41 is limited preferably by the supporting element 46 to impose a maximum fuel flow through the metering orifice 39.

In operation, as the throttle valve 13 is opened to a desired position, intake manifold pressure increases and efiects a contraction of the bellows 45, adjusting the tapered pin towards a more open position, metering an increased fuel flow through the orifice 39. Engine speed will then increase, assuming that there is a constant load on the engine 10, and the increase in speed causing an increase in fuel delivery pressure further acts on the piston 41 to effect a further opening adjustment of the pin 40 until that engine speed is reached at which a further increase would cause a reduction of manifold pressure tending to expand the bellows 45 and prevent any further opening adjustment of the pin 40.

Thus it will be seen that for any position of the throttle valve 13, the fuel metering of the regulator will provide an optimum fuel flow to the engine by virtue of the balance, on the forces adjusting the piston 41, of fuel delivery pressure, as determined by engine speed, and air intake manifold pressure, as determined by throttle position and engine speed, assuming other factors to be constant.

The present device eliminates mechanical connections between throttle and fuel metering device, has only one movable element and is readily manufactured, assembled and adjusted, while ensuring eflicient metering of fuel to the engine.

Although only one embodiment of the invention is described herein, it will be apparent to one skilled in the art to which the intervention pertains that various changes and modifications may be made therein without departing from the spirit of the invention or the scope of the appended claims.

We claim:

1. A fuel metering system for an internal combustion engine having an air intake manifold and a fuel supply means delivering fuel to said engine at a pressure variable in response to engine speed variations, said fuel metering system comprising a fuel flow regulating means operable to meter the fuel being delivered to said engine, and means actuating said fuel flow regulating means to increase and decrease fuel flow respectively in response to increase and decrease of intake manifold pressure and to increase and decrease of fuel delivery pressure, said fuel flow regulating means comprises a regulator housing having a fuel inlet connected with said fuel supply means, a fuel outlet connected with said engine, and a valve means intermediate said inlet and said outlet, and in which said actuating means comprises a pressure responsive means operably connected with said valve means foropening and closingsame, means connecting said pressure responsive means with the engine air intake manifold to operate said pressure responsive means directly proportionately to manifold pressure variations, and means connecting said pressure responsive means with said fuel inlet means to operate said pressure responsive means directly proportionately to fuel pressure at said inlet means, said pressure responsive means being operable to open and close said valve means respectively as air intake manifold pressure increases and decreases and respectively as fuel pressure increases and decreases.

2. The fuel metering system as defined in claim 1 and in which said housing has an orifice openly connecting said inlet and said outlet, and in which said valve means comprises a tapered pin element axially movably disposed in said orifice.

3. The fuel metering system as defined in claim 2 and including adjustable means limiting axial movement of said pin element.

4. A fuel metering system for an internal combustion engine having an air intake manifold and a fuel supply means delivering fuel to said engine at a pressure variable in response to engine speed variations, said fuel metering system comprising a fuel flow regulating means operable to meter the fuel being delivered to said engine, and means actuating said fuel flow regulating means to increase and decrease fuel flow respectively in response to increase and decrease of air intake manifold pressure and to increase and decrease of fuel delivery pressure, said fuel flow regulating means comprises a regulator housing having a fuel inlet pressure chamber, means connecting said fuel inlet pressure chamber with said fuel supply means to conduct fuel supply pressure directly to said fuel inlet pressure chamber, a fuel outlet connected with said fuel inlet pressure chamber, a manifold pressure chamber, means connecting said manifold pressure chamber with said air intake manifold to conduct manifold pressure directly to said manifold pressure chamber, and a valve means intermediate said fuel inlet pressure chamber and said outlet, and in which said actuating means comprises a pressure responsive element in each of the aforesaid pressure chambers and means operably connecting said pressure responsive elements with said valve means, said pressure responsive elements being operable to open and close said valve means respectively as air intake manifold pressure increases and decreases and respectively as fuel pressure increases and decreases. 5. The fuel metering system as defined in claim 4 and including adjustable means operable to limit opening and closing movement of said valve means.

6. The fuel metering system as defined in claim 4 and in which said housing has an orifice openly connecting said fuel inlet pressure chamber and said outlet, and in which said valve means comprises a tapered pin element axially movably disposed in said orifice, said orifice and said chambers being axially aligned, one of said pressure responsive elements comprising a piston disposed in said fuel inlet pressure chamber and extending into said manifold pressure chamber, said piston carrying said tapered pin element and having a fuel pressure sensitive area exposed to fuel pressure in said fuel pressure chamber whereby to move said tapered pin to positions increasing and decreasing the open cross-sectional area of said orifice respectively as fuel pressure increases and decreases, the other of said pressure responsive elements comprising a pressure actuated means supported by said housing in said manifold pressure chamber and connected to said piston therein, said pressure actuated means being operable to move said piston and the tapered pin carried thereby to positions increasing and decreasing the open cross-sectional area of said orifice respectively as air intake manifold pressure increases and decreases and respectively as fuel supply pressure increases and decreases.

References Cited in the file of this patent UNITED STATES PATENTS 2,341,257 Wunsch Feb. 8, 1944 2,891,532 Turlay June 23, 1959 2,898,899 Karpiej Aug. 11, 1959 

